Ambrose will appear in seven of the 10 episodes of the drama’s upcoming season, playing Jilly Kitzinger – “a sweet-talking PR genius with a heart of stone who’s just cornered the most important client of her career … and maybe of all time.”

Production on Torchwood: Miracle Day started Monday, and follows the show making waves last week at TCA press tour when showrunner Russell T. Davies revealed the season’s mind-bending plot:

“One day, on Earth, no one dies,” Davies said. “The next day, no one dies. The day after that, no one dies. The [people who are] dying, keep dying … but don’t actually die. The possibility of death ceases to exist. Which is great for some people. But it’s an instant overnight population boom. The earth relies on people dying.”

Ambrose is best known for her role as Claire Fisher on Six Feet Under, and in more recent years was in the series The Return of Jezebel James and she provided a voice in the film Where the Wild Things Are.

She’ll join Captain Jack and the rest of the Torchwood crew when the series debuts on Starz in July.